The specific aim of this application is to improve myocardial preservation during ischemia. The approach to be used involves: a) employing the pig heart model of global ischemia, b) developing new methods for studying preservation through lipid and free oxygen radical analyses, and c) using established methodology for comparative analyses. The model for global ischemia is the in-sity pig heart preparation on cardjopulmonary bypass. The new methodology to be employed provides for: a) measurement of free fatty acids, their long-chain acyl Co-A and carnitine derivatives, and lysophospholipids in myocardial tissue, and b) an evaluation of the significance of free oxygen radicals in the arrested and reperfused myocardium. The established methods for studying preservatrion involved measuring: a) myocardial high-energy phosphate levels, b) parameters of metabolic function, c) myocardial contractility and compliance, d) regional myocardial perfusion, e) myocardial water content, f) creatine phosphokinase release, g) mitochondrial respiratory function and h) electron microscocopy. The new methodology will be examined and compared to the above established technology for which data is already recorded with standard ischemic and reperfusion times. In the global ischemic heart preparation, the effects of unmodified ischemia and reperfusion and the influence of cardioplegia on fatty acids, long-chain acyl Co-A and acyl carnitine, lysphospholipids, and free oxygen radicals will be studied. Membrane lipid alteration and high-energy phosphate degradation will be differentiated as a factor in the functional and metabolic deterioration of the globally ischemic heart. Studies will focus on increasing myocardial high-energy phosphate levels during cardioplegic arrest and reperfusion. In addition, exogenous lipids will be administered to the non-ischemic cell to differentiate lipid changes from high-energy phosphate degradation as a factor in functional deterioration during ischemia and reperfusion. Cell function will be monitored by using established methodology as described above. The results achieved will provide clinically applicable data for both cardiac surgeons and cardiologists.